1. Field of the Invention
The present invention relates to a sensor having a sensor housing.
2. Description of the Related Art
Published German patent application document DE 102 23 357 A1 relates to a pressure measurement device. The pressure measurement device includes a housing in which a substrate provided with a sensor element and electrical connecting elements is situated. The housing has a first housing chamber which encloses the sensor element and is connected to a first pressure channel of a first pressure connection, and a second housing chamber which is sealed with respect to the first housing chamber and which encloses at least the electrical connecting elements. The housing has a third housing chamber which is sealed with respect to the first housing chamber and the second housing chamber, and which is connected to a second pressure channel of a second pressure connection.
Current developments for pressure sensors pursue a design concept referred to by the term chip-in-housing (CiH). According to this design concept, the sensor chips are glued directly into the sensor housing made of plastic. If two chips, for example a sensor element and a separate electronic component, for example an ASIC, are used, it is necessary to establish multiple electrical connections between the sensor element and the electronic component such as the above-mentioned ASIC, for example. In order to reduce, and in the ideal case totally avoid, the media load to which the electronic component is exposed, the design concept provides that the electronic component and the sensor element are situated in separate chambers. The separation between the two chambers must be designed to be media-tight against exhaust gas, moisture, and other media. According to current approaches, a leadframe injected into the housing of the pressure sensor is used, and gluing, in particular bonding, is carried out on both sides of the leadframe. This technique requires a tightly sealed extrusion coating of a conductor comb, i.e., the leadframe, to avoid penetration of moisture, for example. However, the required media seal-tightness of insert parts is generally not achieved. In addition, a gold or gold-plated surface of the conductor comb may be attacked due to the bonding process, which promotes the formation of corrosion. According to current approaches, the chamber in which the sensor element is accommodated is filled with a gel as additional protection.
For sensors which are in serial production nowadays, in particular pressure sensors which are used in low-pressure areas, the electronic component (ASIC) and the sensor element are also located inside the same housing region, i.e., inside the same chamber. It is also customary for the sensor element and the electronic component, i.e., the ASIC, to be provided within the same silicon chip. An important requirement for new generations of sensors, in particular pressure sensors, is that they must be much more resistant to exhaust gas than preceding sensor generations. It has been shown that the exhaust gas resistance of the sensor element is easer to ensure than the exhaust gas resistance of the electronic component, for example an ASIC. This, in addition to the need for variant management with regard to a flexible assortment of customer-specific forms of sensor elements, likewise having variable ASIC designs, is the reason that the electronic component, in particular an ASIC, and the sensor must be separate from one another.
Thus, the sensor element is located in a chamber which is exposed to the medium, in particular the exhaust gas, while the electronic component, i.e., the ASIC, is located in a separate chamber which is kept from exposure to the media influence.
For low-pressure sensors, two silicon chips are used. One of the two chips is used as a sensor element, while the other is used as an electronic component, for example an ASIC.
An important requirement for this new pressure sensor development is that it must be much more resistant to exhaust gas than preceding generations of pressure sensors. It is generally easier to ensure the exhaust gas resistance of a sensor element compared to ensuring the exhaust gas resistance of an electronic component such as an ASIC. This, in addition to the need for variant management while taking into account customer-specific forms of sensor elements, likewise having variable ASIC designs, is the reason that a sensor element and an electronic component, for example an ASIC, are kept separate from one another.